diff options
| -rw-r--r-- | block/snapshot.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/block/snapshot.c b/block/snapshot.c index 6702c75e42..ccacda8bd5 100644 --- a/block/snapshot.c +++ b/block/snapshot.c @@ -275,13 +275,16 @@ int bdrv_snapshot_goto(BlockDriverState *bs, qobject_unref(file_options); g_free(subqdict_prefix); + /* Force .bdrv_open() below to re-attach fallback_bs on *fallback_ptr */ qdict_put_str(options, (*fallback_ptr)->name, bdrv_get_node_name(fallback_bs)); + /* Now close bs, apply the snapshot on fallback_bs, and re-open bs */ if (drv->bdrv_close) { drv->bdrv_close(bs); } + /* .bdrv_open() will re-attach it */ bdrv_unref_child(bs, *fallback_ptr); *fallback_ptr = NULL; @@ -296,7 +299,16 @@ int bdrv_snapshot_goto(BlockDriverState *bs, return ret < 0 ? ret : open_ret; } - assert(fallback_bs == (*fallback_ptr)->bs); + /* + * fallback_ptr is &bs->file or &bs->backing. *fallback_ptr + * was closed above and set to NULL, but the .bdrv_open() call + * has opened it again, because we set the respective option + * (with the qdict_put_str() call above). + * Assert that .bdrv_open() has attached some child on + * *fallback_ptr, and that it has attached the one we wanted + * it to (i.e., fallback_bs). + */ + assert(*fallback_ptr && fallback_bs == (*fallback_ptr)->bs); bdrv_unref(fallback_bs); return ret; } |